How intrusive is airport security these days? For ten or eleven male passengers, normal TSA screening protocol was so indistinguishable from a predatory stranger arbitrarily groping their genitals that none of them even complained when that happened.

An anonymous airport worker exposed the story on November 18, 2014, telling TSA that a named male security screener at Denver International Airport was groping the genitals of multiple male passengers. Police later described the alleged scheme: "When a male he finds attractive comes to be screened by the scanning machine he will alert another TSA screener to indicate to the scanning computer that the party being screened is a female. When the screener does this, the scanning machine will indicate an anomaly in the genital area and this allows him to conduct a pat-down search of that area.” After the tip more than two months passed.

The screener said to be groping passengers was still employed by TSA. Finally, on February 9, 2015, a TSA official sent to investigate says that he caught the screener in the act and questioned his accomplice, who admitted to helping him on ten prior occasions. Both of the TSA employees were fired. Denver police were informed about a possible sex crime, but a prosecutor declined to file charges in part because TSA declared that it was unable to identify the victim of the groping. They knew only that he was a Southwest Airlines passenger. TSA says that no other passengers filed a complaint about being groped by this screener. Though they were innocent men passing through airport security with nothing in their pants save their genitals, they apparently couldn't tell anything was amiss.

Three other aspects of this story strike me as noteworthy:

1) Kudos to the whistleblower who exposed this misbehavior. But it's shameful that our bureaucracy is one where such tips are made anonymously to avoid punishment or shunning by colleagues rather than openly with the expectation of praise and a reward.

2) Taking more than two months to catch this person seems like an awfully long time. How many shifts did he work after TSA was alerted to his sexual misbehavior?

3) Securing a prosecutable case–that is to say, one with an identifiable victim–would seem to be easy enough, given that everyone going through security is literally required to have identification on their person and is captive in an airport. But the TSA investigator didn't ascertain the identity of the person he witnessed being wrongfully groped. Is this because TSA didn't want their own to be prosecuted? Is it because they didn't want to get sued by the victim? Is it that they weren't willing to tell someone that they could've stopped a needless groping before it happened but let it play out to catch the relevant employee in the act?

TSA officials released a statement about the case.

"These alleged acts are egregious and intolerable," it says. "TSA has removed the two officers from the agency. All allegations of misconduct are thoroughly investigated by the agency. And when substantiated, employees are held accountable."

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Conor Friedersdorf is a staff writer at The Atlantic, where he focuses on politics and national affairs. He lives in Venice, California, and is the founding editor of The Best of Journalism, a newsletter devoted to exceptional nonfiction.